The present invention relates to a device for smoothing a concrete paving surface after the finishing of fresh concrete.
Such devices are needed to make road surfaces from concrete. They may be integrated as an element of a slip form paver or they may be used as a mounted implement of a slip form paver or another road construction machine with a tractor.
Slip form pavers are used to make concrete-paved surfaces, such as roads, concrete runways or the like, with continuous advance. From a truck or with the use of special apparatus, such as charging devices, fresh concrete is poured in front of the slip form paver. Using a distributing screw or a distributing knife, the concrete is first spread evenly transverse to the traveling direction. Thereafter, the concrete is compacted using vibrator means and shaped with a finishing pan to take the desired monolithic profile. Behind the finishing pan, a transverse smoothing means is generally provided that substantially consists of a rigid board reciprocated transverse to the traveling direction, thus smoothing slight irregularities in the still fresh concrete paving. A longitudinal smoothing means is arranged downstream of the transverse smoothing means, which provides an additional smoothing to the still fresh concrete paving.
From German Patent 30 36 234, a device for smoothing a concrete paving surface is known that employs a transverse and a longitudinal smoothing means to remove irregularities in the fresh concrete. The transverse smoothing means consists of a shuttle board located immediately behind a finishing pan. The shuttle board is adjustable in height by two handwheels. The shuttle movement of the shuttle board is caused by an eccentric drive. The longitudinal smoothing means is a smoothing metal sheet hinged on a carriage by means of two pairs of struts, the carriage being movably supported on a cross beam and being displaceable transverse to the traveling direction across the width of the machine. This cross beam is fixedly connected to the machine frame through cantilever arms and it is arranged far behind the transverse smoothing means, seen in the traveling direction. An eccentric drive reciprocates the smoothing metal sheet parallel to the traveling direction. The support of the longitudinal sheet is designed such that the movement of the longitudinal sheet is adapted to the surface contour of the fresh concrete.
It is a disadvantage of this device that the space required by the arrangement of the transverse smoothing means and the longitudinal smoothing means is rather large. The fact that the longitudinal smoothing means extends very far to the rear endxe2x80x94seen in the traveling directionxe2x80x94requires the provision of an additional support for the longitudinal smoothing means. Another problem is that the known longitudinal smoothing means cannot be used when the profile of the concrete paving surface is roof-shaped.
It is the object of the present invention to provide a device of the type mentioned above that allows a working means to be displaced across the entire working width even if the concrete paving surface is roof-shaped.
Advantageously, according to the present invention, the transverse smoothing means for making a roof-shaped profile of the concrete paving surface consists of two transverse smoothing boards hingedly connected at the center of the working width, and a working means is movably attached to the transverse smoothing means and is movable on the transverse smoothing means across the entire working width of the machine frame. Thus, the invention provides that the transverse smoothing means serves as a guiding means for an additional working means adapted to be displaced across the working width. Thereby, the structural length of the machine can be reduced significantly and an additional cross beam used as a guiding means for the working means can be omitted. Further, it is guaranteed that the working means will exactly follow the roof-shape of the concrete paving surface defined by the transverse smoothing means. When mounting prolongating segments with a working width up to 16 m, the guiding means for the working means is prolonged at the same time without any further rearrangements.
Preferably, the transverse smoothing means comprises a carriage movable across the entire working width of the machine frame, the working means being mounted on the carriage. Thus, the transverse smoothing means serves as a guiding means for a carriage, the guiding means preferably consisting of rails on which the rollers of the carriage can run.
In a preferred embodiment, the rail ends facing each other are provided with a track segment extending parallel to the rails, the track segment bridging the gap occurring between the rails when setting a roof-shaped profile of the concrete paving surface, and the carriage has twin rollers that take support on the rails, as well as on the track segment. The track segment allows for a smooth passage from the guiding means of one transverse smoothing board to the guiding means of the other transverse smoothing board. Thus, the working means can be moved across the working width such that it exactly follows the roof-shaped profile of the concrete paving surface.
The track segment is preferably fastened to one of the two transverse smoothing boards. In order to distribute the load, it is also possible to divide the track segment into two parts, the part with the upper guiding means being mounted to one of the transverse smoothing boards, while the other part of the track segment with the lower guiding means is fixed to the other transverse smoothing board. Here, the two track segments may be slidably supported at each other.
Preferably, the transverse smoothing means is pendulously suspended at the machine frame via coupling members. Thus, a swinging transverse movement of the transverse smoothing means is made possible.
Preferably, the transverse smoothing means is suspended at the machine frame in the manner of a parallelogram.
The working depth and the longitudinal angle of inclination of the transverse smoothing means may be adjusted continuously. The longitudinal angle of inclination refers to an adjustment angle of the transverse smoothing means in the traveling direction.
In a particularly preferred embodiment, the working means is a longitudinal smoothing means. The invention is particularly advantageous for use with a longitudinal smoothing means. In a longitudinal smoothing means that requires a large space, reducing the structural length is an important advantage.
Preferably, the drive required for moving the working means transversely across the working width is arranged on a structural member that is stationary relative to the machine frame, not on the transverse smoothing means.
Here, the longitudinal smoothing means may be adjusted independent of the transverse smoothing means. This is of importance in preventing interferences of the movements of the transverse smoothing means and the longitudinal smoothing means.
Preferably, the device is integrated in a slip form paver so that the structural length thereof can be reduced significantly. The device may also be mounted as an add-on device on another road construction machine, or it may be an independent machine with running gears of its own.
Various features and advantages of the present invention will become evident from the following description of a preferred embodiment taken in conjunction with the accompanying drawings.